1. Field of the Invention
This invention relates to an electrode used in a solar cell.
2. Technical Background
Since an electrode for silicon solar cell is required to have low electrical resistance to facilitate improved efficiency. The problem is that Silver which has lower resistance gets high contact resistance on the contact with silicon substrate. To solve the problem, JP2006-93433 discloses an electrode which is formed on a p-type conductive layer by using a conductive paste which comprises silver powder, an organic vehicle, glass frit and at least one kind selected among boron powder, an inorganic boron compound, and an organic boron compound.
JP2003-152200 discloses a conductive paste for a solar cell electrode comprising Ag and TiO2. JPS59-11687 discloses a conductive paste for a solar cell electrode comprising Ag and Ti. JP2002-141520 discloses an electrode for a solar cell comprising inorganic compounds of Ti, Co or Zn. However, even though these electrodes are capable of lowering the contact resistance of the N layer in semiconductors composed of solar cell semiconductor N and P layers, the resistance of the P layer naturally remains high. US 2008/0230119 disclose an electrode comprising Ag and Pd, which is capable of bringing about low contact resistance in both the n-layer and p-layer. However, when the conductive paste is sintered at elevated temperature, the resistance ends up increasing. In view of the above problems, there is a need to provide an electrode for a solar cell, which provides good conductivity in both the N layer and P layer, and does not limit the sintering temperature for sintering the electrode.